Keep getting null when sending an array of data using AJAX to Laravel Controller

Question

I am trying to send an array of data from client-side using AJAX to the backend Laravel controller. The problem is that I keep getting null when data-dump in the controller.

I have tried many possible solutions online and nothing is working for me. I need your help to know where I have gone wrong or missed. Thanks in advance.

This is the route

Route::post('/event/going/{id}', ['as' => $s . 'going-post', 'uses' => 'PagesController@goingForEvent']);

This is the controller

public function goingForEvent(Request $request, $id)
{
            dd(Input::get('result'));
}   

This is the HTML code

<a data-url="{{route('public.going-post', $singleEvent->id)}}" id="imGoing" class="ui attached positive button">I'm Going</a>
                    <div class="or"></div>

This is the AJAX code

<script>
    $.ajaxSetup({
        headers: {
            'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
        }
    });

    $("#imGoing").click(function() {

        var url = $(this).data('url');
        console.log(url);

        //var x = url.substr(url.lastIndexOf('/') + 1);
       // console.log("/event/going/" + x);

        swal({
          title: 'Multiple inputs',
          html:
            '<input type="text" id="firstName" class="swal2-input">' +
            '<input type="text" id="lastName" class="swal2-input">' +
            '<input type="email" id="email" class="swal2-input">',
          preConfirm: function () {
            return new Promise(function (resolve) {
              resolve([
                $('#firstName').val(),
                $('#lastName').val(),
                $('#email').val(),
              ])
            })
          },
          onOpen: function () {
            $('#firstName').focus()
          }
        }).then(function (result) {
            var stuff ={fn:result[0],ln:result[1], em: result[2]};

            console.log(stuff);

            $.ajax({
                url: url,
                type: "POST",
                data: {result:JSON.stringify(stuff)},
                processData: false,  // tell jQuery not to process the data
                contentType: false   // tell jQuery not to set contentType
            }).done(function( data ) {
                //console.log(data);                    
            });
        }).catch(swal.noop)
    });
</script>

Result after using $request->all() at the controller